Method for controlling liquid chromatograph

Abstract

The method for controlling a liquid chromatograph according to the invention is a method for controlling the liquid chromatograph including a liquid delivery pump, a flow path connected to the liquid delivery pump, a flow path switching valve (an auto purge valve, an injection valve, and a stream select valve) provided in the flow path and configured to switch a plurality of connection destinations for the flow path, and a pressure sensor configured to detect at least one of a liquid delivery pressure of the liquid delivery pump, a flow path pressure in the flow path, and a pressure applied to the flow path switching valve. The method includes rotating the flow path switching valve during liquid delivery from the liquid delivery pump, and determining whether a bubble remains in the flow path based on a pressure fluctuation when the pressure lowered by rotating the flow path switching valve increases.

1 . A method for controlling a liquid chromatograph including
 a liquid delivery pump,   a flow path connected to the liquid delivery pump,   a plurality of streams provided in the flow path and including a pressure sensor configured to detect at least a flow path pressure in the flow path and a separation column configured to separate a component of a fluid flowing in the flow path, and   a flow path switching valve configured to select one stream to be used for analysis from the plurality of streams,   
       the method comprising:
 rotating the flow path switching valve during liquid delivery from the liquid delivery pump, and determining a stream in which a bubble remains in the flow path based on a pressure fluctuation when the pressure lowered by rotating the flow path switching valve increases. 
 
     
     
         2 . The method for controlling a liquid chromatograph according to  claim 1 , wherein
 each of the plurality of streams includes a first switching valve positioned upstream of a flow of a fluid, and a second switching valve connected to a downstream of the first switching valve via the flow path, and   based on the pressure fluctuation when the first switching valve is rotated and the pressure fluctuation when the second switching valve is rotated, it is determined whether a bubble remains in a flow path from the liquid delivery pump to the first switching valve and whether a bubble remains in a flow path from the first switching valve to the second switching valve.   
     
     
         3 . The method for controlling a liquid chromatograph according to  claim 2 , wherein
 a time fluctuation for returning to a specified pressure is used as a determination criterion.   
     
     
         4 . The method for controlling a liquid chromatograph according to  claim 2 , wherein
 the determination is executable during both an operation and maintenance.   
     
     
         5 . The method for controlling a liquid chromatograph according to  claim 2 , further comprising:
 storing, in a database, information when it is determined whether a bubble remains in the flow path, and diagnosing whether there is a possibility of bubble generation based on the corresponding information.   
     
     
         6 . The method for controlling a liquid chromatograph according to  claim 2 , wherein
 the first switching valve is an auto purge valve, and the second switching valve is an injection valve.